Blood tests can be used to identify deviations from normal blood pictures, by virtue of which the presence of a pathological anomaly or a risk factor can, for example, be established, or it may at least indicate that further investigation is necessary or advisable. Of course, also a healthy blood picture can be established.
U.S. 2003/0175167 describes a device by which a quantity of blood can be taken up into a chamber, wherein the blood is diluted and then at least in part pressed through a filter. The filter is selected such that at least the blood plasma from the blood can pass the filter and be collected in a collection space, while at least the blood cells from the blood can not pass through the filter and remain in the chamber. Subsequently, a seal is provided in the passage between the chamber and said collection space, in order to prevent exchange of plasma and cells. The device is then send to a laboratory by mail, in order to carry out an analysis on the plasma. It is particularly important that the separation between the plasma and red blood cells is maintained, because otherwise the plasma is useless for many tests thereafter. The analysis of the blood plasma is done, for example, by spectral analysis.
U.S. 2004/0133146 describes a device, whereby blood is drawn using a thin tube, which blood is then delivered in a chamber, after which it is pressed against a filter with the help of a plunger, such that at least the blood plasma is forced through the filter and at least the red blood cells are left behind in the chamber. The separated blood plasma can then be examined, for example, by spectral analysis.
Compared to whole blood analysis, these devices provide the benefit that the blood does not need to be centrifuged. With this, it suffices to draw less blood and tests can be performed more quickly.
These prior art devices, and the methods in which they are used, have the disadvantage that they still require relatively long periods of time before a test result is known to the patient whose blood has been drawn or to the therapist. After all, while only small amounts of blood need to be drawn and while centrifugation is no longer required, the analysis must be carried out in a laboratory, so that relatively long periods of time are required for shipping and processing. Moreover, it may be experience as a disadvantage to the patient that others can become aware of the test results, even earlier than the patient himself.
Furthermore, a device is for example known from U.S. Pat. No. 4,477,575 wherein use is made of reagents, whereby a drop of blood is deposited on top of a filter. Driven by capillary action and/or gravity blood plasma is guided through a filter layer while the red blood cells are left behind on the filter. In or around the filtering layer a reagent is provided which can react with a substance in the blood plasma. Thereafter, a visual inspection of the visible surface of the device it can be established (through discoloration or emerging lines) whether or not the analyte is present in the blood. DE 29 22 958 describes multi-layer filters having different reagents for different pathological or otherwise indicative factors in blood.
Such a device offers the advantage that the test can be performed by a patient or in his or her presence, so that the time for obtaining the test results can be significantly shortened.
However such tests still require several tens of minutes or longer, which is undesirable in many cases. In addition, these tests have the disadvantage that they are very susceptible to, for example, contamination from outside, since the device is open, while in addition the degree of separation and thus the amount of blood plasma obtained cannot not be determined with sufficient precision. In particular when multi-layer filters are used with different reagents, this disadvantage is exacerbated because it is unclear how much blood plasma is provided to which layer of the filter and the runtime, and thus the time until result of the test, increases with the number of filter layers.
The invention aims to provide a device and/or process for analyzing blood for the presence of an analyte.
In particular, it is an objective of the present invention to provide a process and/or device for the relatively rapid separation of at least plasma and red blood cells from whole blood and then analyze at least the blood plasma. A further objective of the invention is to provide a process and/or device with which a user can perform a blood test autonomously and relatively fast.
It is another objective of the invention to provide a device and/or process for the separation and analysis of blood, which gives indications on thresholds or values of one or more analytes present in blood, in particular FABP.